Hourglasses which prove very useful soon. Hop, it left you .... minutes! If the first time, some students are having, then they become reactive. When the hourglass is turned over, they know they must get to work if they do not want to be penalized. In addition, they are cute. Students come as soon as possible to my office for tossing and turning them! The description is consistent. Small, yes, but with the indication of time on one of the peaks. And frankly, at that price, we can only be satisfied!
